<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8" />
        <meta http-equiv="X-UA-Compatible" content="IE=edge" />
        <meta name="viewport" content="width=device-width, initial-scale=1.0" />
        <title>链式调用</title>
    </head>
    <body>
        <script>
            let p = new Promise((resolve, reject) => {
                reject("ok");
            });

            p.then(v => {
                console.log(v);
            }).then(v => {
                console.log(v);
            }, r => {
                console.warn(r); // ok
            }).then(v => {
                console.log(v);  // undefined
            }, r => {
                console.warn(r); // 
            });
        </script>
    </body>
</html>
